Management of patients with chronic disease consumes a significant proportion of the total health care expenditure in the United States. Many of these diseases are widely prevalent and have significant annual incidences as well. Heart failure prevalence alone is estimated at over 5.5 million patients in 2000 with incidence rates of over half a million additional patients annually, resulting in a total health care burden in excess of $20 billion. Heart failure, like many other chronic diseases such as asthma, COPD, chronic pain, and epilepsy, is event driven, where acute de-compensations result in hospitalization. In addition to causing considerable physical and emotional trauma to the patient and family, event driven hospitalizations consume a majority of the total health care expenditure allocated to the treatment of heart failure.
Hospitalization and treatment for an acute de-compensation typically occurs after the de-compensation event has happened. However, most heart failure patients, for example, exhibit prior non-traumatic symptoms, such as steady weight gain, in the weeks or days prior to the de-compensation. If the caregiver is aware of these symptoms, it is possible to intervene before the event, at substantially less cost to the patient and the health care system. Intervention is usually in the form of a re-titration of the patient's drug cocktail, reinforcement of the patient's compliance with the prescribed drug regimen, or acute changes to the patient's diet and exercise. Such intervention is usually effective in preventing the de-compensation episode and thus avoiding hospitalization.
Patients with health conditions can receive medical devices such as subcutaneously implanted medical devices, supercutaneously coupled medical devices, and/or medical devices otherwise coupled to the body. For example, chronic heart disease patients may receive medical devices such as pacemakers, implantable cardioverter defibrillators (ICDs), and heart failure cardiac resynchronization therapy (CRT) devices. Currently, the physician that installs pacemakers, ICDs, and/or other medical devices requires their patients to make clinic visits periodically, usually once every three or four months, in order to verify if their medical device is working correctly and programmed optimally. Device follow-ups are usually performed by the nurse-staff assisted by the sales representative from the device manufacturers. Device follow-ups are labor intensive and typically require patients to make multiple clinic visits.
In an effort to limit the number of follow-ups necessary to monitor the device and the data that it acquires, an advanced patient management system may provide a communication infrastructure. This infrastructure allows the medical device to communicate over long distances at virtually any time with a backend system that monitors the medical device and the patient. Furthermore, this backend system allows monitoring of the patient on a more frequent basis than ordinary follow-up visits can practically allow. The back end system may communicate with the medical device through an external unit such as a repeater that the patient keeps in close proximity. Conventionally for many medical devices, the external unit communicates directly with the medical device through an inductive coupling which requires that the patient hold a wand over the location of the medical device. Alternatively, short range radio frequency transfer may occur between the external device and the medical device. The external unit then transfers information from the medical device through a telephone line or other network interface to the back end system. Furthermore, it is likely that medical devices will employ longer range wireless telecommunication abilities to establish communication directly with the backend system through, for example, cellular networks.
The conventional approach to communicating with the medical device has drawbacks in that the patient lacks privacy due to the medical device recording data about the patient continuously or at pre-determined times. This data being recorded may include health related data but may also include other information, such as the location of the patient where the medical device incorporates a geonavigational positioning system or cellular phone technology. Additionally, this data may be streamed from the medical device to an external device where it is recorded and/or forwarded to the backend patient management system. The patient has little ability to control when the medical device is recording data that is subject to be transferred or when it is transmitting the data being recorded to the external devices and systems. Many patients likely prefer the ability to control such data transfer so that data about the patient is not always available for others to see, but such control is not possible with conventional systems.